The most common and most likely answer to this crossword clue is the 7 letter word MADNESS
M
A
D
N
E
S
S
More clues leading to the result MADNESS
- Great anger with object returned in bulk
- 21 back in crowd — foolish behaviour
- Folly to finish back in service
- Finish up interrupting church service? That's insane
- Insanity of head pursuing deterrent theory
- Confusion spread by broadcast and stupidity
- Group from the ’80s and Blur in trouble
- Aim the wrong way in complete lunacy
- Frenzy to stop returning when enthralled by religious ceremony
- Target revolutionary in service in 27 10’s state
Buddy explains!

The straight part
We know that "group" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case group = madness.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MADNESS mean?
MADNESS noun- The state of being mad; insanity; mental disease.
- Rash folly